A device is known that measures the densities of objects captured in an image. For example, JP-A 2014-6586 (KOKAI) discloses that the number of specific objects is measured based on the area ratio of the foreground region with respect to the captured image.
However, if a plurality of types (classes) of objects is captured in an image, then it difficult to accurately calculate the density of each object class captured in the image due to false recognition of the object class.